[Background] Translation initiation factors of the 4E and 4G protein families mediate resistance
to several RNA plant viruses in the natural diversity of crops. Particularly, a single point mutation
in melon eukaryotic translation initiation factor 4E (eIF4E) controls resistance to Melon necrotic spot
virus (MNSV) in melon. Identification of allelic variants within natural populations by EcoTILLING
has become a rapid genotype discovery method.[Results] A collection of Cucumis spp. was characterised for susceptibility to MNSV and Cucumber
vein yellowing virus (CVYV) and used for the implementation of EcoTILLING to identify new allelic
variants of eIF4E. A high conservation of eIF4E exonic regions was found, with six polymorphic sites
identified out of EcoTILLING 113 accessions. Sequencing of regions surrounding polymorphisms
revealed that all of them corresponded to silent nucleotide changes and just one to a non-silent
change correlating with MNSV resistance. Except for the MNSV case, no correlation was found
between variation of eIF4E and virus resistance, suggesting the implication of different and/or
additional genes in previously identified resistance phenotypes. We have also characterized a new
allele of eIF4E from Cucumis zeyheri, a wild relative of melon. Functional analyses suggested that this
new eIF4E allele might be responsible for resistance to MNSV.[Conclusion] This study shows the applicability of EcoTILLING in Cucumis spp., but given the
conservation of eIF4E, new candidate genes should probably be considered to identify new sources
of resistance to plant viruses. Part of the methodology described here could alternatively be used
in TILLING experiments that serve to generate new eIF4E alleles.

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